Pressure and temperature responsive fuel metering and injection pump



7- c. E. SUMMERS PRESSURE AND TEMPERATURE RESPONSIVE FUEL METERING ANDINJECTION PUMP Filed Aug. 14', 1943 3 sheets-sheet 1 R w m m w w W I sa. B E L O. Y B 3 mm 1 o ATTO RN EYS okiwt .wski E C. E. SU AND TEMPERATERI 2,414,617 UEL 3 Sheets-Sheet 2 F E P I SM .NU P PM S s 09 E RR II TE O M MT Jan. 21-, I947.

PRESSURE NE N6 AND I Filed- Aug.

0 o o o o 0 H INVENTOR. 'GALEB E. SUMMERS BY Jan. 21, 1947.

C. E. SUMMER PRESSURE AND TEMPERATURE RESPONSIVE FUEL METERING ANDINJECTION PUMP Filed Aug. 14, 1943 3 Sheets-Sheet 3 o v 4% FIGA.

35 43A 4IA INVENTOR. CALEB E. SUMMERS ATTO RNEYS Fate ted Jinn. rearstares PRESSURE AND TEMPERATURE RIEIPN- EEWE FUEL ME'K'E EUIMIP RINGAME) lENJLE C'EIUN 4 illaiins. l

The present invention relates to multicylinder internal combustionengines, and more specifically to means for supplying fuel to theseveral cylinders.

As is well. known, the supplying of fuel to engines from a conventionalcarburetor may be accompanied by a number of difiiculties such asunequal distribution, mixture variation due to changes in temperatureand barometric pressure and others.

It is among the objects of the present invention to overcome suchdifficulties by providing means for supplying fuel to the individualcylinders by injection of finely atomized liquid fuel under highpressure and automatically varying the amount of injected fuel inaccordance with load, temperature and barometric pressure.

Another object is to provide a fuel metering means which providessubstantially equal distribution to the several cylinders.

Another object is to provide fuel supply means which automaticallyadjusts the amount of fuel atomized into the cylinders to accord withthe amount of air admitted thereto.

Another object is to provide a fuel metering means which imposes nocoming air charge.

Another object is to provide a fuel supply pump in. which the body mayhe made of a material having a high coefiicient of expansion andplungers of a material having a relatively low expansion rate, soconstructed that extreme variations in temperature do not substantiallychange the clearance between the plunger and its sleeve.

Another object is to provide a high pressure fuel pump in which oilpressure lubrication is maintained around the plungers.

Still another object is to provide a fuel pump in which the clearancebetween the plunger and v the bore is automatically generated by forcinga plunger into a slightly undersized soft-metal lined bore.

Other objects and advantages will be apparent to those skilled in theart upon reference to the following description and the accompanyingdrawings in which Figure 1 is a side elevation, partly in section, of afuel pump constructed in accordance with the present invention.

Figure 2 is a top plan view of the same with part of the cover brokenaway.

Figure 3 is an end elevation thereof.

Figure 4 is a, section on line t-t of Figure 1 of a part of the camshaft.

Figure 5 is a detail view of the bellows-actuated shaft.

Figures 6 and 7 show respectively a side eleva tion and a section of apreferred cam construction for large units.

in the drawings, the fuel pump is indicated as consisting of a closedcasing of two parts, the lower portion to housing some of the workingparts and the upper portion comprising a pair of cylinder blocks ii andMA, and a sealing cover it, and having the other working parts.

The cylinder blocks, each containing one half the number of pumpcylinders, are shown oppositely arranged in the same plane, so that thepistons for all of the cylinders may be actuated from a single actuatingshaft. It will be under stood that to adapt this device to variousmotors restriction on the inand services, the pump cylinders here shownup posed, may be arranged in line in V form or radial.

Only one cylinder and piston is shown in detall, but any desired numbermay be used, de-

pending upon the number of engine cylinders to be served. In the presentinstance, the number of outlets shown in Figure 2, indicates a total oftwelve.

As shown in Figure 1, each of the cylinders it is lined with a sleeveiii provided with annular reliefs iii on the inside and pressed intoplace in the casing ill. The arrangement of the reiieis ii and instaggered relation and slightly overlapping as shown, permits the use ofa rous metal for the piston and sleeve and a body of a, light alloy of amuch higher coefficient of expansion, and still maintain the smallpiston clearance even under extreme temperature changes. The outer endsof the cylinders in are shown as being closed by a cylinder head illprovidilng for each cylinder a pump chamber it into which fuel is drawnfrom a common supply past a disc valve 2il'tensioned against its seat bya suitable spring 2 5. From the chamber 2! the fuel is forced throughoutlet 25 controlled by valve 26, the latter being resiliently held inits seat by a suitable spring 2?.

Operating in each of thecylinders iii or more correctly, sleeve is, is apiston lid, and since a minimum clearance between cylinder and pistonmust be had, it is preferred to coat, preferably by plating, the insideof the sleeve with ,a relatively soft bearing metal such as cadmium, tinor silver, to provide an inside diameter a few tenths of a thousandth ofan inch less than the diameter of the piston. It should be understood,of course, that the piston should be polished and ,by suitable bearingsengine.

4| for a cam 33,

indicated for a second cam 33 (see Fig. 4)

- portion and a 3 straight, so that when forced into the plated sleeve,a substantially perfect fit is obtained.

For each of the pistons 3|! is'provided a rather strong spring 3|,suitably anchored to a stationary part of the cylinder block and biasedto move the piston on its outward or intake stroke, while the rearwardend of each piston 30- is provided with a roller 32 cooperating with acam 33 during the inward or pumping stroke, the cam providing theactuating force,

The cams 33 are fixed to a shaft 35 shown in Figure ,1 as tubular, saidshaft being supported 33A, Fig. 2, said shaft being driven at halfengine speed (by suitable means, not shown) and mounted between thecylinder blocks H and HA, each cam actuating a piston 30 in one cylinderof block II and one in the aligned cylinder in block HA.

The earns 33 are of course so located radially upon the shaft 35 andthepump outlets 25 so connected as to accord with the firing order of theThe mechanism thus far described, in its actuation, will deliver at eachof the strokes of the pistons, maximum amounts of fuel, so in order tovary the delivery, the pump is provided with means for varying thelength of piston stroke and such means, in the present invention, isalso constructed and arranged to cause such variation in accordance withthe" engine load and also in accordance with variations in temperatureand pressure.

This varying or regulating means is shown in Figures 1, 2 and 4, andconsists of a'pair of other cams 40, 4|, arranged adjacent each of theearns 33 and movable around shaft 35 so as to block at the proper pointthe movement of the pistons 30 outward of the cylinders on their intakestroke, the shoulder 30A contacting the cam 4|, at any point from nostroke to full stroke, depending upon the angular position of cam 4|.Thus an amount of fuel less than the maximum is drawn into the cylinder,at the point-at which the piston movement is arrested and consequentlythe incoming fuel charge, being determined by the con-, ditions of load,temperature and pressure existing at the time. These other cams aremounted loosely 'on the shaft 35 and are shown at 40 and a second pair42 and 43 being Each of the cams 40 to 43, consists of a cam bearingportion 40A to 43A (see Fig. 4) and on each cam portion is provided anear 40B.

Surrounding the bearing portions 40A, etc. is a sleeve 45 carrying ateach end a pair of arms 45A and 453, each carrying an car 450, and asecond pair of arms 45D and 45E, each of which carries a stop lug 45F.The ears 40B and 45C extend outwardly from the cams 40 and 4| and serveas abutments for springs 45 which hold the cams 40, etc. resilientlyagainst the stops 45F. Thus it will be seen that when there is a suddendemand forv power, the bellows easily rotates the cams 40-, etc. eventhough some are acting on the plungers, for the movement is down hill.When less power is needed, the bellows takes a position compressing thesprings 45 until the cam 33 lifts the plungers.

As may be noted from Figure 4, a single sleeve 45 is arranged to coactwith the movable cams 40, etc. for two of the cams 33. This means that,in the pump illustrated with twelve cylinders, there will be threesleeves 45.

Each of the three sleeves 45 is provided with but it should beunderstood that 4 an actuating arm 5|! and each arm 50 connected by asuitable link'5l to a crank arm 52 fixed upon a rotatable shaft 53. Theshaft 53 is in turn rotatable through arms 54 connected through link 55to the bellows 60, of which two are shown, one or several :nay be usedwithout departing from the invenion.

The sealed bellows 50 is mounted within the lower part of the housing l0and is filled with an inert gas. In order to make the bellows moresensitive to outside temperatures and also to reduce the volume of itsgas contents so that the maximum expansion will not overstrain the metalof the bellows a cylindrical displacement member 5| is used to seal thebellows. This member 5| is integral with the base 52 of the sealedbellows 50 and is sufficiently large to substantially fill the bellows,leaving only the bellows ribs and a small part of the remaining interiorfor the inert gas.

. The member 5| is of course closed at its inner end but is open at theouter end and thereby provides a large surface susceptible to theinfluence of outside temperatures and, since the sealed in gas isdispersed in a thin layer on the outside of member 5|, it receives andreacts quickly to any temperature change outside or inside of housingl0.

The bellows 50 is mounted in the housing I a in a cylindrical guide 53and since the housin is filled with oil, well above the guide, thelatter is perforated as shown, to permit free movement, of the bellows.Further in order to protect the bellows against wear, bearing rings 54may be provided.

Iii-order to submit the bellows 50 to the influence of load conditions,the housing i0 is, as stated above, sealed and provided with a nipple 10or other connecting means whereby theinterior of the housing may beconnectedto the intake manifold of the engine.

In the operation of the device, when the conditions of load andtemperature indicate a full charge of fuel in the respective cylindersof the engine, the cams 4|! and 4|, and the corresponding cams will bein approximately the position shown in Figure 1, that is, they will notinterfere with the movement in and out of the pistons 30. Consequently,each piston 30 draws in and forces out a full charge. When, however, apart throttle and 'a high outside temperature, or either conditionexists, the bellows 50 will expand and move the cams 40, 4|, etc. intoposition to blockmore or less the outward movement of pistons 30 with aconsequent pumping of only a part charg of fuel.

It is now apparent that the inert gas sealed within the bellows 50 issubjected to the same temperature andabsoiute pressure as the chargeentering the cy' derand therefore its density is proportional to thedensity of the air change. If, therefore, we have a measure of thevolume of charge entering a cylinder, the position of the bellows actingthrough selected lever ratios and a proper contour of cams 40- could bemade to control the stroke of the plunger 30, to give tion of the rateof the spring 62A, provided withproper stops or controls, will give aclosely approximate correction for the variation in volumetricefllciency of an airplane engine from level to the stratosphere.

Since the method of controlling the rate of fuel discharge is byarresting the pump plunger at any required point in its intake stroke,it is desirable to make that the velocity of the plunger 30 issubstantially uniform throughout the stroke so the shock of such arrestand also the shock when the cam 38 again contacts the roller 32 for thedischarge stroke, will be uniform and at a minimum. In order to cushionsuch shock, a slight resilience may be provided by making the cams 33 inthe form shown in Figures 6 and 7, that is, by forming the cams of sheetmetal so that the cam surface is on an overhanging flange capable of aslight give. The uniform speed of the plunger an the sudden stop at theend of the stroke, gives uniform atomization and a minimum drool.

The relative proportion of the 360 33 that are used for the maximumstroke and the plunger 30 is to of the cam discharge maximum intakestroke of the be determined for best results in each service. Preferablythe discharge stroke shall not be'more than 120" which leaves 240 forthe intake stroke which is relatively slow and easy for the fuel tofollow.

It should be noted that with the extremely small clearance of pistons30, very high pressures will, be developed in the fuel delivery to thethe central relief l8 through the inlet I 8K.

the contour of the cam 33 such the parts are inposition to supply apartial charge, the injection is somewhat delayed and such delay favorsstratification, and thereby facilitates firing of the lean charge.

I claim:

I manifold of said engine, a body of oil in said It should further benoted that due to the slope of the cams 40, 4|, etc., they will have atendency to move to full charge position and. therefore, the directionof rotation of shaft 35 should be such as to tend toneutralize this bythe friction of the parts.

One of the many advantages to be derived from the use of the presentdevice lies in the fact that it acts also as a timer for the fuelinjection. When housing. an expansible an contractible element CALEB E.SUMMERS.

